Add translation and rotation

src/hittable.rs

@@ -19,6 +19,30 @@ pub struct HitRecord<'material> {
     pub material: &'material Arc<Material>
 }
 
+impl<'material> HitRecord<'material> {
+    pub fn normalized(&mut self, ray: &Ray) {
+        let dot = ray.direction().dot(&self.normal);
+        let front_face = dot < 0.0;
+        let normal = if front_face { self.normal } else { -self.normal };
+        self.normal = normal;
+        self.front_face = front_face;
+    }
+    /*pub fn normalized(& self) -> Self {
+        let dot = ray.direction().dot(self.normal);
+        let front_face = dot < 0.0;
+        let normal = if front_face { self.normal } else { -self.normal };
+        HitRecord {
+            point: self.point,
+            normal,
+            t: self.t,
+            u: self.u,
+            v: self.v,
+            front_face,
+            material: self.material
+        }
+    }*/
+}
+
 pub trait Hittable {
     fn hit(&self, ray: &Ray, t_min: f64, t_max: f64) -> Option<HitRecord>;
     fn bounding_box(&self, time0: f64, time1: f64) -> Option<Aabb>;
@@ -74,19 +98,18 @@ impl Hittable for Sphere {
         }
         let point = ray.at(root);
         let normal = (point - self.center) / self.radius;
-        let dot = ray.direction().dot(&normal);
-        let front_face = dot < 0.0;
         let (u, v) = Sphere::uv(&normal);
-        let normal = if front_face { normal } else { -normal };
-        Some(HitRecord {
+        let mut rec = HitRecord {
             point,
             normal,
             t: root,
             u,
             v,
-            front_face,
+            front_face: false, // Will be set during normalied()
             material: &self.material
-        })
+        };
+        rec.normalized(ray);
+        Some(rec)
     }
     fn bounding_box(&self, _time0: f64, _time1: f64) -> Option<Aabb> {
         let s = Vec3::new(self.radius, self.radius, self.radius);